Improvement in inks for canceling stamps



UNITED STATES PATENT QFFIOE.

JOSEPH E. HOVER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO HIMSELF AND THOMAS SHAW.

IMPROVEMENT IN INKS FOR CANCELING STAMPS.

Specification forming part of Letters Patent No. 194,966, dated September 11, 1877; application filed July 12, 1877.

- of certain chemicals with the usual coloring matter and ordinary materials forming canceling-ink, which compounds an ink that is based upon the principle of acting chemically when applied to colored stamps or other tinted surfaces that will charge or discharge the color of which the stamp is composed.

The object of the invention is to incorporate a chemical material with any ink or coloring matter used for ordinary stamping, which chemical material is for the sole purpose of destroying the color and the sizing of which the stamp is composed, so that in case the canceling-ink bewashed off byilly-disposed parties there will be a complete and permanent discoloration of the face of the stamp, with additional liability of the surface of the paper to wash off by reason of the partial destruction of the sizing material.

In order to enable others to use and practice my invention, I will proceed to describe the composition employed.

I find the best proportion and kind of material for this purpose are one pound of ordinary lamp-black to five or six pounds of commercial hydrochloric acid, and after they are well incorporated together there is added from four to five pounds of linseed or other equivalent oil used for the manufacture of printinginks. The whole is well ground into a suitable condition for printing use. Glycerine may be substituted for the oil.

The efiect of the acid is to decompose the coloring matter of the stamp, and to destroy the sizing material in the stamp, which effectually defeat the restoration for original use of any such canceled stamp.

It will be evident that the proportions given and the materials used may be considerably modified without any alteration in the result. I therefore do not wish to confine myself to the exact proportion" or kind of material used.

What Ido claim,and desire to secure by Letters Patent, is-

The incorporating of the chemical material composed of ordinary lamp-black, commercial hydrochloric acid, and linseed-oil, as set forth, or their evident equivalents, for a cancelingink that has for its object the destroying of the coloring matter or printed surface that composes the stamp, substantially as and for the purpose set forth.

JOS. E. HOVER.

Witnesses:

T. SHAW, WM. B. HUGHES. 

